SPOKANE, Wash. (AP) -- Saul Phillips ran over to the fans in green and yellow, threw his arms in the air and screamed at the top of his lungs.

No one could hear the excitable North Dakota State coach. There was too much noise from the Bison celebrating the biggest win in school history.

Lawrence Alexander hit a 3-pointer with 11 seconds left to force overtime and freshman Carlin Dupree scored four points in the final 75 seconds as No. 12 seed North Dakota State knocked off Oklahoma 80-75 Thursday night.

The Bison (26-6) picked up their first NCAA tournament win by rallying in the final minute and then outlasting the No. 5 seed Sooners in overtime. Alexander finished with a career-high 28 points, but it'll be his falling-down, fist-pumping celebration after the tying 3-pointer that will be replayed in Fargo for years.

Dupree came on in the closing seconds of overtime after Taylor Braun fouled out. He hit two free throws and scored on a difficult baseline leaner with 41 seconds left.

Cameron Clark led Oklahoma (23-10) with 25 points.

TrayVonn Wright added 14 points and Marshall Bjorklund scored 13, including a hook shot to open an overtime session where the Bison never trailed. Braun, his body beaten up throughout the game, finished with 11 points and six rebounds before fouling out.

Clark scored 16 in the final five minutes of regulation and overtime. Isaiah Cousins added 17 points and Jordan Woodward had 13, making up for leading scorer Buddy Hield being limited to nine points on 4 of 14 shooting.

Whenever the Bison needed a big shot, Alexander answered. With Braun bottled up by the Sooners defense, it fell to Alexander to pick up the scoring load. The most he had scored all season was 20 points and his career-high came in 2011 as a freshman.

No basket was bigger than the 3 that forced overtime. Braun drove into the lane and was cut off. Alexander was his only option. After briefly struggling to get the handle, he rattled in his fourth 3-pointer of the game.

Oklahoma gave NDSU a chance at tying by twice missing foul shots in the final minute. Woodward split free throws with 39 seconds left and Cousins did the same with 26 seconds remaining, giving the Bison a chance to tie.

Oklahoma had chances to win in regulation. With the entire lower bowl standing, the Sooners got off three shots. Hield's open 3 rimmed off, Woodward's free-throw line jumper was short and Cousins' reverse layup attempt at the buzzer never caught the rim.

NDSU scored the first four points of overtime on baskets by Bjorklund and Alexander, but Clark's 3 pulled Oklahoma even at 70. Braun put the Bison ahead with 1:39 left 72-70 on a driving layup. After he fell to the court, Braun got tangled with Clark, who appeared to inadvertently kick Braun in the face. No additional fouls were called, but Braun fouled out seconds later reaching in as Clark attempted to shoot.

Clark hit both, but four seconds later Dupree - a 58 percent free throw shooter - hit a pair to put the Bison back in front. Following an Oklahoma miss, Dupree drove baseline and scored instead of running off time. It was the shot of an inexperienced freshman, but Phillips didn't mind. It put the Bison up by four and started the celebration.